<html>
<head>
    <meta charset="UTF-8">
    <title>javaScript</title>
</head>
<body>
</body>
<script type="text/javascript">
    document.write("使用JavaScript脚本语言循环输出hello world!")
    for(var i=0;i<3;i++){
        document.write("<h1>hello world!</h1>");
}
</script>
</html>